Pretty Print Cocoa Containers

Due to a pretty obnoxious behavior in Foundation, the commonly used containers don't actually allow you to print out pretty descriptions of your own custom objects. This is a dirty ugly hack which gets you that capability.

In a flash

I replace the implementations of descriptionWithLocale:indent: on commonly used containers.

Example

In the output, pay special attention to how the object in the dictionary changes after swizzling:

Before swizzling:
<ExObj:0x7fc098415140
    _ivar0 = Foo
    _ivar1 = 42
    _ivar2 = {
            anotherObject = "<ExObj:0x7fc098414d80\n    _ivar0 = Bar\n    _ivar1 = 1\n    _ivar2 = {\n        }>";
        }>

After swizzling:
<ExObj:0x7fc098415140
    _ivar0 = Foo
    _ivar1 = 42
    _ivar2 = {
            anotherObject = <ExObj:0x7fc098414d80
                _ivar0 = Bar
                _ivar1 = 1
                _ivar2 = {
                    }>;
        }>

How to enable

This is turned on by use of defines created by compiler flags. For example, if I wanted to turn everything on, I'd add the -DDEBUGPRINT_ALL flag to my build settings.

DEBUGPRINT_ALL: NSArray, NSMutableArray, NSDictionary, NSMutableDictionary, NSSet, NSMutableSet, NSOrderedSet, NSMutableOrderedSet
DEBUGPRINT_NSARRAY: NSArray, NSMutableArray
DEBUGPRINT_NSDICTIONARY: NSDictionary, NSMutableDictionary
DEBUGPRINT_NSSET: NSSet, NSMutableSet
DEBUGPRINT_NSORDEREDSET: NSOrderedSet, NSMutableOrderedSet

Alternatively, if you want to include the JRSwizzle library, you can swizzle the changes in an out at runtime:

DEBUGPRINT_SWIZZLE: Exposes the fspp_swizzleContainerPrinters function.

Also, you can use the DEBUGPRINT_SPACES_PER_INDENT macro to define how many spaces per level of indentation. The default is four.

Whitespace Trimming

By default, whitespace is trimmed from Foundation containers (a distinct difference from Foundation's default behavior). To illustrate the difference, consider the following:

{
    foo =     (
        bar
    );
}

Notice the whitespace after foo =? With whitespace trimming enabled (as it is by default), that disappears.

{
    foo = (
        bar
    );
}

This can make some kinds of descriptions much easier to work with. Please see the Whitespace guide for more information.

To disable whitespace trimming, use the DEBUGPRINT_NO_SUPPRESS_WHITESPACE_ALL macro.

WTF man, why?

I like my objects formatted nicely when they print out to the console. It helps when debugging applications.

mysteriouspants / NSContainers-PrettyPrint